installing washer/dryer in basement where none have come before

I recently bought a 100 year old home in Portland, OR and need to install a washer/dryer in the house. I will not employ a plumber to help. I have so far been planning to put the set in the basement, but I have questions regarding hookups.

I have an older-style Maytag Neptune (like 1999 or so) and have not purchased a dryer, but it will be a used, older model.

The main sewer drain is probably original, made of what appears to be cast iron. My basement is dug-out dirt, about 7 feet tall. The main sewer pipe comes up straight vertically from below the 7 foot grade and then splits off at about 6 feet into multiple y-splits to accomodate the toilet, shower, bathroom sink and kitchen sink. The y-splitters are some iron (or the same material as the original pipe) and some newer black plastic.

I am not concerned about the hot/cold hookups - they are pretty straightforward. But I do have questions about the sewer hose.

If I put the washer on the 7 foot grade, the flow of sewer water from the washer would go up the currently attached built-in hose, into a standpipe, down the standpipe, then up (!!) 6 or more feet to join the existing sewer. I don't want to mess with the cast iron sewer piping if possible, and would rather add-on another y-splitter on the black plastic sewer from, say, the kitchen sink.

Am I going to need some kind of sump pump at the bottom of the standpipe? Can I make this work as proposed? Or does the standpipe have to flow downhill from the mouth?

I will happily explain my situation further if anyone asks for clarifications.

You have me thoroughly confused. The drain cannot go down the standpipe, and then up 7', unless the standpipe end is higher than that. In any case, having 7' of water in the pipe when the washer starts to drain will be a positive way to have it overflow the standpipe. Without seeing the current installation, we cannot even begin to tell you if there is a "safe" way, (i.e., without overflowing and flooding the basement), to connect to that existing piping. The only sure thing is that if you connect to the cast iron pipe going into the floor you will need more help than we can give over the Internet.

As HJ indicates, your description is difficult to follow and. there are several important issues involved. For example, cutting into a vertical cast iron stack can be VERY DANGEROUS. Cast iron is extremely heavy and you could end up pulling drains loose above. You trap and vent this installation properly, and there are limits to what a washer can pump. It really would be in your best interest to bite the bullet and hire a plumbing contractor to install your drain properly. It's not just to meet code, there are things that we novices do that aren't strictly up to code but do work, but there are things that have to be done correctly because an improperly installed drain will give you more headaches than you want to imagine and cost you more to straighten out later.

I don't know about a Maytag, but the highest a Whirlpool washer can pump water is 8'. And only if there is no back pressure (which would occur if you pumped it down and then up a standpipe.) You will need a sump pump or preferably, have a plumber make you a proper drain at the below grade point.